@ Parnparsley- The knife you are thinking of is a meat cleaver. This is best for working with large pieces of meat that need to be split into more manageable sizes, and for cutting through bones. Think of a cleaver as more of a meat hatchet. A hybrid butcher knife is simply a meat cleaver that comes to a point.
A true butcher knife is sometimes called a scimitar knife because it resembles the shape of these Persian swords. It can come to a sharp point, or be slightly bulbous at the end; adding weight to the blade.
Probably the most important knife to a butcher is the boning knife, also called a fillet knife. This knife is used to trim meats, and to carve meat form the bone. If you are working with large cuts of meat, you may want to invest in all three of these. If you will actually be working with whole animals, you may also want to purchase a curved-blade skinning knife. I hope this helps.